Loading, firing and unloading mechanism for a firearm with a laterally actuated breech closure



March 7, 1961 Filed Oct. 7, 1959 FQ.P1.(:C) l3\( LOADING. FIRING AND UNLOADING MECHANISM FOR A FIREARM WITH A LATERALLY ACTUATED BREECH CLOSURE 5 Sheets-Sheet 1 4 LNWQQVZUR.

March 7, 1961 R. H. COLBY LOADING. FIRING AND UNLOADING MECHANISM FOR A FIREARM WITH A LATERALLY ACTUATED BREECH CLOSURE Filed Oct. 7, 1959 5 Sheets-Sheet 2 Big EL IN VEN TOR. Rid-n11? l1 ILEUTE March 7, 1961 COLBY 2,973,693

LOADING, FIRING AND UNLOADING MEC ISM FOR A FIREARM WITH A LATERAL ACTUATED BREECH CLOSURE Filed 001;. 7, 1959 5 Sheets-Sheet 5 mum Riifhur 93 as d4 14 BY J 423 194 cg.

March 7, 1961 R. H. COLBY 2,973,693

LOADING, FIRING AND OADING HANISM FOR A FIRE w A LATE LY ACTUAT BREECH CLOSURE Filed Oct. 7, 1959 5 sheets sheet 4 u 681: no um 1 lung ZEJBEZEL INVENTOR. Eirzhurfl Hflnly Q. d. @fl d March 7, 1961 COLBY LOADING, FIRING AND. UNLOADING MECHANISM FOR A FIREARM WITH A LATERALLY ACTUATED BREECH CLOSURE Filed Oct. 7, 1959 5 Sheets-Sheet 5 INVENTOR.

LOADWG, FIRING AND UNLOADING MECHA- NISM FER A FIREARIW WITH A LATERALLY ACTUATED BREECH CLOSURE Richard H. (Dolby, outh Hadley, Mass, assignor to the United States of America as represented by the Secretary of the Army Filed Oct. 7, 1 959, Ser. No. 845,043

7 Claims. (Ci. 89-169) (Granted under Title 35, U8. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.

This invention relates to automatic firearms which are recoil operated and more particularly to the breech mechanisms thereof. This application is a continuation-inpart of a previous application, Serial No. 429,706, filed May 13, 1954 and entitled Operating Mechanism for a Short Firearm.

It is an object of this invention to provide for such firearms a breech mechanism which is compactly designed so as to require a small-sized receiver suitable for mounting in a limited space, as in a tank.

It is another object of this invention to provide for such firearms, which have a laterally actuated breech closure member, a loading and unloading mechanism which is connected to the combined mass of the barrel and barrel extension during functional operation of the mechanism thereby permitting a reduction in the mass of the loading and unloading mechanism so as to require a minimum of space in the receiver.

It is a further object of this invention to provide a carrier for the ramming of cartridges into the firearm barrel and the extraction of the fired cases therefrom with such'functions being performed by a rammer and an extractor which are vertically spaced and which extend forwardly from the carrier so as to form a clearance for the passage of the breech closure member when the rammer and extractor are in joint contact with the rim of the chambered cartridge.

It is still another object of this invention to provide a double cam device for actuating the carrier responsive to the reciprocation of the barrel and thereby increase the angular relationship between an accelerator which actuates the carrier and the cam path means for smoothness of operation.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

Fig. 1 is a side view of the firearm partially cross-sectioned to show the arrangement of the-parts when the firearm is in battery;

Fig. 2 is a view similar to Fig. l but showing the relationship of the parts when the firearm is in recoil posi- 'tion;

Fig. 3 is a fragmentary view similar to Fig. l but showing a cartridge engaged by the front end of the rammer during forward movement of the carrier;

Fig. 4 is a view taken along line 4-4 of Fig. 2;

Fig. 5 is a view taken along line 55 of Fig. 1;

Fig. 6 is a view taken along line 6-6 of Fig. 2;

Fig. 7 is a view taken along line 7-7 of Fig. 1;

Fig. 8 is a view taken along line 8-8 of Fig. 7;

Fig. 9 is a view taken along line '99 of Fig. 1;

Fig. 10 is a fragmentary side view of the cam arrangement for actuating the accelerator; and p Figil'lis a view taken alongline 11- -11 ofFig'. =1.

'in the forward and rearward positions.

2,973,693 Patented Mar. 7, 1961 Shown in the figures is a firearm 12 including a rectangular receiver 14 and a feeding mechanism 16 having a laterally disposed tray 18 which is mounted on the top of the receiver. Feeding mechanism 16 is of conventional type and is adapted to successively index linked cartridges 20 at a throat 22 communicating with the inside of receiver 14. A barrel 24 is slidingly mounted in the front end of receiver 14 for reciprocation in recoil and counterrecoil strokes responsive to forces produced by the discharge of a cartridge 20 in a chamber 26 of the barrel. A barrel extension 28 is connected to barrel 24 for reciprocation therewith by coupling means, such as shown at 30, and is bifurcated by a vertically disposed channel 32 which provides communication between chamber 26 and an ejection port 34 in the bottom of receiver 14. Channel 32 also forms apair of vertically disposed side plates 36 which have sliding engagement with the corresponding sides of receiver 14. A pair of springs 38 are disposed between barrel extension 28 and the rear end of receiver 14 for biasing barrel 24 and the attached barrel extension forwardly in a counterrecoil stroke after being compressed during the recoil stroke thereof.

Cartridges 20 are successively transferred from throat 22 into chamber 26 by a carrier 46 which is mounted between side plates 36 for longitudinal reciprocation in channel 32 between a forward and a rearward position in axial alignment with barrel 24. Engagement is made between carrier as and the cartridge 20 which is indexed in throat 22 by a rammer 42 which extends integrally forward from the top of the carrier. Rammer 42 is provided with a front end 44 which is disposed for contact with the base of the throat indexed cartridge during movement of the carrier to the forward position. A

guide portion 46 is disposed at the front end of throat 22 to engageably direct cartridge 2t downwardly into chamber 26 while being moved forwardly by rammer 42. As cartridge 2th assumes alongitudinal position in chamber 26, front end 44 slides over a rim 47 of the cartridge for frictional contact of the rim with an underside 48 of rammer 42 when the cartridge is fully chambered.

An extractor St is journaled to the underside of carrier 46 by means of a laterally disposed pin 54 for pivotal movement in the samevertical plane occupied by rammer 42. Extractor 5%) extends forwardly substantially parallel to rammer 42 so as to jointly contact cartridge case rim 47 therewith and to form a clearance 56 having a purpose to be described hereinafter. A hook 58 is provided at the front end of extractor 50 for releasable engagement with an extractor groove 62 -in cartridge 20 so as to remove fired case 64 thereof from chamber 26 during movement of carrier 40 to the rearward position thereof. A spring 66 is disposed between extractor 50 and carrier 40 rearwardly of pin 54 for biasing hook 58 inwardly. The displacementof fired case 64 by the bias of spring 66 is opposed by the contact of rim 47 with underside 48 of rammer 42 and such engagement between the 'ramrner and extractor maintains the fired case longitudinally disposed while being carried rearwardly from chamber 26 by carrier 40. A ramp 60 is formed on the front end of hook 58 for cammingly moving the hook over rim 47 for engagement with extractor groove 62 during forward movement of carrier 40 after cartridge 20 is stripped by contact thereof with the walls of chamber 26.

Carrier 40 is actuated between the forward and rearward positions thereof responsive to reciprocation of barrel 24 by means of an accelerator 68 which is pivotally disposed in channel 32 on a pin 76 mounted laterally beportion 74 adjacent the right one of the side plates 36 adjacent the bottoms thereof and spaced equidistantly "between-the location of the rear end'of the carrier when Accelerator 68 includes a beam 72 which extends upwardly from a hub portion 74 adjacent the right one of the side plates 36 so as to be spaced from the left one thereof sufliciently to leave unobstructed a pathway for the passage of fired case 64 to ejection port 34 as hereinafter described. A

roller 76 is rotatingly mounted to the left side of the free end of beam 72 for sliding engagement with a vertical groove 78 in the rear portion of the right side of carrier 40 for converting pivotal movement of accelerator 68 to translational movement of carrier 40 and to connect the carrier to the accelerator without free movement therebetween.

The forward and rearward positions of carrier 40 are spaced sufiiciently for a cartridge to be transferred thereby from throat 22 into chamber 26 and fired case 64 extracted therefrom during the reciprocation of the carrier. However, the rearward position need .not be spaced for an overtravel of. carrier 40-so as to gain momentum beforerammer 42 contacts the indexed cartridge, as in conventional firearms, because as hereinlationship to the longer length of beam 72 for a mechanical advantage to assist cam paths 84 and 86 in actuating carrier 40 for full travel thereof between the forward and rearward positions.

After cartridge 20 is transferred into chamber 26 by rammer 42, the base of the cartridge is supported for discharge by a breech member 96 which is slidingly disposed in barrelextension 28 for substantially lateral movement adjacent the breech of barrel 24 between a breech open and a breech closed position. Breech member 96 includes an anvil 98 which, when the breech member is in the breech open position, is clear of chamber 26 so that fired case 64 may be removed therefrom after described, the masses of barrel 24 and barrel ex- I tension 28 are connected to the carrier during the ramming and extraction operation thereof. combined mass of barrel 24and barrel extension being connected to carrier 40, the mass thereof may be reduced so as to occupy little space in receiver 14.

Accelerator 68 is actuated to move carrier 40 between Also, with the v the forward and rearward positions thereof during the rearward half of the reciprocaltravel of barrel 24 and barrel extension '28 by means of a double cam device including a rammer arm '80 and an extractor arm 82 which extend integrally from hub portion 74 for cooperation with cam paths 84 and 86 in receiver 14 as described hereinafter. Such double cam arrangement provides a much smoother actuation of accelerator 63 because, in order to move carrier 40 between the forward and rearward positions thereof, beam 72 swings through an angle of 75 which would approach a dead center contact between the engaging portions of the accelerator and a cam if only one thereof was used.

In order to save space in receiver 14 sothat accelera' "tor 68 may be journaledto barrel extension 28, adjacent the bottom thereof, rammer arm .89 and extractor arm 82 extend upwardly from hub portion 74, With beam 72 vertically disposed, rammer arm 80 extends upwardly and rearwardly from hub portion 74 in back of the beam and at an angle relative thereto which is equal to 'one-half that.through which the beam must swing to actuate carrier 40,'and extractor arm.82iextends up- 'wardly and forwardly from the hub portion on the op- ;posite side of the beam at a similar angleyrelative thereplate 88 which is fixed to the right side of. receiver 14 and is engaged by a follower 90 rotatingly mounted to .the free end of rammer arm 80.. Cam path 84extends arcuately upward and forward in acam plate 88. and

is formed was to pivot beam, 72 between the rearward Cam pa d-1 8 4 is formed in vertically disposedhcam -96 is being actuated to the breech open position so as not to interfere with the subsequent movement of car sponsive to reciprocation of barrel extension28 and without free movement between. follower 94 and the. cam .path while engaged. ..As best shown in Eig. ,10, cam paths 84- and 86-are so formed that transfer is made .between accelerator 68 and theecam pathsat the vertical posifionof beam 72 without loss of contact between'the accelerator-and thecam paths; The lengths of rammer arm-80 and extractor-arm 82 have a predetermined reor cartridge 20' transferred thereinto. When breech member 96 is actuated to the breech closed position, anvil 98 is inserted between extractor 50 and rammer 42 in clearance 56 to support the base of the chambered cartridge 20 for discharge.

A roller 100 depends from the base of breech member 96 for sliding engagement with a cam groove 102 provided in a shelf 103, extending rearwardly from the front end of receiver 14, for converting longitudinal displacement of barrel extension 28 to lateral movement of the breech member. Cam groove 102 includes an arcuate portion 104 which is disposed so as to actuate breech member 96 to the breech closed position during the final half of the counterrecoil movement of barrel extension 28 and to the breech open position during the first half of the' recoil stroke thereof. 'A linear portion 106 extends rearwardly from arcuate portion 104 and slidingly receives roller 100du'ring the rearward half of the reciprocal travel of barrel extension 28 to secure breech member 96 in the breechopen position during the ramming and extracting operations of carrier 40. A dwell portio'n108 extends forwardly from the opposite end of arcuate portion 104 to receive roller 100 when barrel 24 is in full' forward position'to lock breech member-96 in the breech closed position. The length of dwell portion 108 is predetermined so that, when roller 100 enters arcuate portion 104 therefrom to actuate breech member 96 to the breech open position, sufficient time has elapsed for a reduction in the gas pressurein barrel 24 to where it is safe to uncover fired case 64hut with enough gas pressure remaining in the barrel ,to assist in the extraction of the fired case from chamber 26.

Cartridge 20, after being transferred to chamber 26, Iis discharged by. a hammer 110 which is journaled on a shaft 112 mounted through the left one of the side plates 36. Hammer' 110 is disposed in channel 32 adjacent cam plate 88 and, therefore, clear'of a pathway through channel 32 for passage of fired case 64 to ejection port 7 34. Hammer 110 is provided with a striker portion 116 and an extension 118 disposed on the opposite side of shaft 112 from such striker portion. is mounted to extension lls by means of an axle 119 which extends therefrom so that the wheel is disposed for engagement with 'an arcuate engagement surface 122 recessed in the top front corner of cam plate 92. Engagementsurfac 122 is engaged by wheel during the initial recoil movement of'barrel 24 for pivoting hammer 110.to the cock position while breech member rier 40 to the rearward position. Hammer 110 is'held 'in the cock'position until barrel extension 28 is adjacent forward battery position and breech member 96 is locked in breech closed position by' the rolling contact of wheel 12 0 witha topls'ide 124 oflcarn plate 92 lead ing from engagement surface 122. When wheel 120 is adjacent engaging 'surface 122 during counterrecoil movement. of barrel extension 28, hammer n 110. is retained in. the cock position by the releasable engagement thereof by a sear 126 which is mounted. to the left. one of the side plates 36... Hammer 110 is biased toathe fir ing position by aspring-b'iased plunger128 which is dis- A wheel 120 extractor.

posed in barrel extension 28 so as to pres s'a'gainst extension 118.

Connection between striker portion 116 and primer 132 of a cartridge 20 in chamber 26 is made by a firing pin 134, which is disposed through anvil 98 for sliding longitudinal movement against such primer when breech member 96 is in the breech closed position, and a firing pin extension 136 which is angularly disposed through carrier 48 so that the rear end of the firing pin extension is contactable by the striker portion and the front end is contactable with firing pin 134 when the carrier is in the forward position and breech member 96 is in the breech closed position. Firing pin extension 136 is slidingly disposed in carrier 48 so that the energy of hammer 110 may be transferred to firing pin 134.

Fired case 64 is ejected from receiver 14 by an ejector 138 which depends from the underside of feed tray 18 so as to contact the upper portion of rim 47 when the fired case, gripped between extractor 58 and rammer 42, clears breech member as. Through the contact of ejector 138 with rim 47, fired case 64 is pivoted around hook 58 and expelled downwardly through channel 26 and out ejection port 34. As stated hereinbefore, there is very little overtravel required of carrier 48 for the ramming operation thereof and, therefore, in order to have as early an ejection of fired case 64 as possible so as not to interfere with the ramming function, a vertically disposed notch 140 is provided through the rear portion of breech member 26 to provide a clearance for thedownward passage of the neck of the fired case to advance the point at which ejector 188 may contact the fired case. Firearm 12 is held inoperative by means of a trigger 142 which releasably holds barrel extension 28 in the 'recoil position.

When firearm 12 is in battery, barrel extension 28, under the pressure of the springs 38, is biased to the forward position along with barrel 24. Carrier 48, consequently, is in the forward position thereof in barrel extension 28 with rammer 42 and extractor 50 jointly contacting rim 47 of a cartridge 20 which is housed within chamber 26 and is supported for discharge therein by breech member 96 which is disposed in the breech closed position with anvil 98 inserted between the rammer and Hammer 118 is releasably held in cock positicn by sear 125, and firing pin extension 136'is in registry with firing pin 134 which is in alignment with primer 132 of the chambered cartridge 20.

The release of hammer 110 is automatically controlled by sear 126 through a conventional release mechanism noted at 127 in Fig. 5. When hammer 118 is released by sear 1 26, the energy imparted thereto by spring-biased plunger 128 is transmitted through firing pin extension 136 to firing pin 134 for ignition of primer 132 of chambered cartridge 28. Upon discharge of chambered cartridge 20, barrel 24 with barrel extension 28 connected thereto is energized for recoil movement in receiver 14, whereupon roller 188 on breech member 96 moves along dwell portion 188- of cam groove 182 to prevent movement of the breech member until the gas pressure in the barrel is reduced sufliciently for the fired case 64 to be unblocked yet with sufiicient pressure remaining in the barrel so that, when the roller enters arcuate portion 104 to move the breech member to the breech open position, the extraction of the fired case is assisted by the residual 'gas pressure. Also, during the initial portion of the recoil movement of barrel extension 28, hammer 110 is pivoted to the 'cock position by the engagement of wheel 128 with engaging surface 122 and is retained in the cock position during the remainder of the recoil movement of the barrel extension.

travel, follower 94 on extractor arm 82 becomes engaged by cam path 86 whereupon accelerator 68 is pivoted a:

move carrier 40 rearwardly and the mass of barrel 24 and barrel extension 28 is connected to carrier 4ilthr'o1igh such engagement together with the engagement of roller 76 on theend of beam 72 with groove 78 in the carrier. With the rearward'movement of carrier 48, fired case '64 is removed from chamber 26 through the engagement of hook 58 with extractor groove 62 in the fired case, and the fired case is maintained longitudinally disposed during the extraction stroke through the joint engagement of rim 47 by extractor 50 and rammer 42. When beam 72 is vertically disposed, extractor arm 82 becomes disengaged from cam path 86 and rammer arm 88 engages cam path 84 to complete the actuation of carrier 40 to the'rearwa-rd position thereof. As carrier 40 nears the end of the rearward position thereof, the base of fired case 64 contacts ejector 138 for disengagement from the extractor and ejection through channel 32 in barrel extension 28 and out ejection port 34.

At the end of the recoil stroke of barrel 24, the springs 38, which were compressed during the recoil stroke thereof, energize barrel 24 for the subsequent counterrecoil stroke. During the initial half of the counterrecoil stroke of barrel extension 28, follower 90 on rammer arm 80, which is engaged by cam path 84, pivots accelerator 68 forwardly until beam 72 reaches its vertical position when follower 90 leaves cam path 84 and follower 84 enters cam path86 to complete the movement of carrier 40 to the forward position. During forward movement of carrier 40, front end 44 of rammer 42 contacts the cartridge 20 indexed in throat 22 to transfer the cartridge into chamber 26 of barrel 24. When the rammed cartridge 20 becomeslongitudinally disposed in chamber 26, front end 44 slides over rim 47 for contact of underside 48 therewith and,'during continued forward movement of carrier 40, hook 58 rides over rim 47 for engagement with extractor groove 62.

During the final half of the counterrecoil stroke of barrel extension 28, roller enters arcuate portion 184 of cam groove 102 to actuate breech member 86 from the breech open to the breech closed position with anvil 98 being laterally inserted between rammer 42 and extractor 50 to support the base of cartridge 20 in chamber 2t: for discharge and aligns firing pin 134 between primer 132 of the'chambered cartridge and firing pin extension 136. Also, during the final movement of barrel extension 28 to the forward battery position, wheel 128 of hammer lltlmoves adjacent engagement surface 122 to release the hammer, into engagement by sear 125, and roller 100 enters dwell portion 108 to lock breech member 96 in the breech closed position. t

From the foregoingit is clearly apparent that there is provided herein a loading, firing and unloading mechanism of compact design so as to be housed within a receiver having a short length for mounting Within a small space, as in a tank, with the mechanism being simple in design, rugged in construction and positive in operation.

Although a particular embodiment of the invention has been described in detail herein, it is evident that many variations may be devised within the spirit and scope thereof and the following claims are intended to include such variations.

1 claim:

1. In a firearm having a receiver, a barrel mounted in the receiver and provided with a chamber for the discharge of a cartridge having an annular rim adjacent the base thereof and a breech member slidingly disposed in the receiver adjacent the barrel chamber for lateral rcciprocation between a breech open and a breech closed position responsive to forces produced by the discharge of the cartridge in the barrel chamber, a loading and unloading mechanism including a carrier slidingly disposed in the receiver for longitudinal reciprocation between a rearward position and a forward position adjacent the breech of the barrel, a rammer extending integrally forward from said carrier, an extractor pivotally disposed on said carrier for forward extension therefrom; to coengage with said rammer the rim of the cartridge when in the barrel chamber for removing the fired case of the cartridge therefrom during movement of said carrier to the rearward position thereof and for maintaining the fired case longitudinally disposed during the recoil travel of said carrier, and a clearance formed between said extractor and rammer for passage of the breech member to the breech closed position when said carrier is-in the forward position thereof and said rammer and extractorare in co-engagement with the rim of the chambered can tridge. r a

2. In a firearm having a receiver, a barrel mounted in the receiver and provided with a chamber for the discharge of a cartridge provided with an extractor groove and a rim formed thereby and a breech member disposed in the receiver adjacent the barrel chamber for lateral reciprocation between a breech open and a breach closed position responsive to forces produced by the discharge of the cartridge in the barrel chamber, a loading and unloading mechanism inclosed in the receiver andincluding a carrier disposed for longitudinal reciprocation between a rearward position and a forward position adja: cent the barrel chamber, a rammer extending integrally forward from said carrier, an extractor pivotallyv mounted on said carrier so as to'extend forwardly-therefrom,-a clearance formed between said rammerand extractor for passage of the breech member to the breech closed position when said carrier is in the forward-position, a hook disposed on the forward end of said extractor for engagewhereby said hook is maintained in engagementlwith thev extractor groove and'the fired case is longitudinally dis.- posed when removed from the barrel chamberrby. said extractor during movement of said carrier tothe rearward position thereof. h, t

-3. In a'firearm having a receiverwith a barrel slidingly disposed therein for reciprocationrres pons'ive to forces produced by the discharge of a cartridge in a chamber thereof, the cartridge being provided withla rim adjacent the base thereof and a centrally located primer, a barrel extension connected to the barrel'for reciprocation therewith and providedwith a-channelvertically disposed therein to provide communication-between the barrel chamber and an'ejection'portin the underside of the receiver, a breech memberslidingly disposed in the barrel extension for lateral reciprocation-therein adjacent the barrel chamber, cooperating cam means disposed in'the receiver and on the breech memberfor actuating the breech member between a breech open and a breech closed position responsive -to longitudinal reciprocation of the barrel extension, and a firing pin extending longitudinally through the breech member for movement against 'the primer of-the chamberedcartridge for discharge thereof, a mechanism including 'a;carrier slidingly disposed in the barrel extension for longitudinal reciprocation in the channel-between a rearward position and a forward position adjacentthe barrel-chamber, a rammer extending integrally forward from said carrier,

an extractor pivotally disposed onfsaid carrier for-forward extension therefrom to c'o-engage with said rammer the rim of the cartridge when in the barrel chamber,- a

clearance forme'd'between said extractorand rammerfor passage of the breech member to' the breech closed posi- "tion whenisaid' carrier is in'the forward' position thereof and said rammer and extractor are in "co-engagement with'the'rim of the chambered cartridge,-a spring-ener- V 8, v to provide space in the channel for the ejectionof the fired case of the cartridge therethrough after discharge, and a firing pin extension slidingly mounted in'said carrier and disposed angularly therethrough for transferring the energy in said hammer to the firing pin when the br'eechmemberl is in the breech closed position and said carrier is in the forward position thereof.

4. In a firearm having a receiver with a barrel slidingly disposed therein for longitudinal reciprocation in a recoil and a 'counterrecoil stroke responsive to the forces produced by the discharge of atcartridge in a chamber of the barrel, the cartridge having a rim formed by an annular extractor groove, a barrel extension connected to .the breech of the barrel for reciprocation therewith in the receiver and provided with a vertically disposed channel to-provide communication between the barrel chamber and an ejection port in the bottom of the receiver, a breech member slidingly disposed in the barrel extension for lateral reciprocation adjacent the breech of 'the barrel between a breech open and a breech closed position, and a feeding mechanism mounted on the top side of the receiver for successively indexing the cartridges in a throat leading into the receiver, a.

loading and unloading mechanism inclosed in the receiver rearwardly of the breech of the barrel and including a carrier slidingly disposed in the-barrel extension for longitudinal reciprocation in the channel thereof between a rearward position and a forward position adjacent the'breech of the barrel,1a rammer extending integrally forward from the top of said carrier and disposed to transfer the cartridges from the throat into the barrel chamber during movement of said carrier to the forward position thereof by means of a front end having contact with the base of the cartridge until the cartridge is longitudinally positioned in the barrel chamber, an extractor 'pivotally mounted on the underside of said carrier so as to extend forwardly therefrom, a clearance formed between'said rammer and extractor for passage of the breech member to the breech closed position when said carrier is in the forward position, a hookdisposed on the forward end of said extractor for engagement with the extractorgroove of the chambered cartridge when said carrier is in the forward position thereof spr ing means disposed between said extractor and said carrier for biasing'said hook into the extractor groove to remove the fired caseof the cartridge from the barrel chamber during movement of said carrier to the rearward position thereof, and an underside ofsaid rammer disposed for frictional contacttwith the rim of. the cartridge when longitudinally disposed in -the' barrel chamber to oppose the displacement of the fired case by said spring means for maintaining said hook in engagement-with the extractor groove and the fired case longitudinally disposed during extraction from the barrel chamber. I a t 5.--The loading and unloading mechanism as defined in claim 4 and'including an accelerator provided with ahub portion journaled to thebarrel extension on a pin extending laterally through the barrel extension adjacent thebottom thereof and equidistantly between the loca- -tions of therearend of said carrier when in'the forward and rearward positions thereof, a beam extending integrally upward from said hub for displacement betweenfa. rearward and a forward position spaced equidistantly from a vertical position, a rammer arm extendingintegrally upward and rearward from said hubtjportion and an extractor arm extending upwardly andfor- ;wardly from said hub portion when saidbea'm is in the vertical position, and camemeans for actuating said carrier between the forward "and'rearward positions thereof, said cam means including a roller mounted to the free end of said .beam for slidingengagement with a t 7 vertical groove'in, the adjacent side of said carrier and adjacent the rear. end thereof for converting pivotal movement of said accelerator to translational movement of said carrier without free movement therebetween, a first cam path disposed in the receiver for cooperation with a follower rotatingly mounted to the free end of said ramrner arm for pivoting said beam between the rearward and vertical positions thereof responsive to reciprocation of the barrel extension, and a second cam path disposed in the receiver for cooperation with a follower rotatingly mounted to the free end of said extractor arm to controllably pivot said beam between the forward and vertical positions thereof responsive to reciprocation of the barrel extension, said first and second cam paths being arranged so as to pivot said beam between the forward and rearward positions thereof during the rearward half of the reciprocal movement of the barrel extension and for one of said first and second cam paths to be engaged by said accelerator during actuation of said carrier between the forward and rearward positions thereof to connect the mass of the barrel and barrel extension to said carrier during reciprocation thereof.

6. The loading and unloading mechanism as defined in claim 4 and including an accelerator disposed within the channel in the barrel extension, said accelerator including a hub journaled to the barrel extension to mount the accelerator for pivotal displacement and a beam extending from said hub, cooperating cam means on said beam and said carrier for converting pivotal displacement of said accelerator to longitudinal translation of said carrier and connecting the barrel and barrel extension to said carrier for relative longitudinal movement, and cam means interposed between said accelerator and the receiver for converting the translation of the barrel to pivotal displacement of said accelerator and transferring the energy in the barrel and barrel extension through said accelerator to said carrier.

7. The loading and unloading mechanism as defined in claim 4 and including an accelerator mounted on the barrel extension for pivotal displacement through an arc of a predetermined angularity which is of the order of 75, cam means on said accelerator and said carrier for converting pivotal displacement of said accelerator to longitudinal translational displacement of said carrier, a first cam means fixed to the receiver and disposed for sliding engagement by said accelerator for converting longitudinal displacement of the barrel and barrel extension to pivotal displacement of said accelerator through one-half of the arc, and a second cam means fixed to the receiver and disposed for sliding engagement by said accelerator for converting continued longitudinal displacement of the barrel and barrel extension in the same direction to pivotal displacement of said accelerator through the remaining half of the arc.

References Cited in the file of this patent UNITED STATES PATENTS 642,018 Ternstrom Jan. 23, 1900 830,511 Lehmann Sept. 11, 1906 2,389,960 Dobremysl Nov. 27, 1945 2,411,979 Rataiczak Dec. 3, i946 

